The present invention relates to a printing apparatus, and specifically relates to a printing apparatus wherein regulation of positional errors due to backlash and elongation of a wire or belt of carriage driving means is performed in response to a print start command signal in printing in a right margin flush printing mode, a centering printing mode or the like.
Generally, printing apparatuses such as electronic typewriters are constituted in a manner capable of setting to a typewriter mode, a memory mode (memory-display mode) or the like, and in the typewriter mode, the apparatuses can be set to a right margin flush mode (hereinafter referred to as RMF mode) wherein a desired character string or document can be printed while justified to the right margin position, and to a centering mode (hereinafter referred to as CTR mode) wherein, for example, a title of the document can be printed at the center of a print line.
When this RMF mode is set, a carriage is moved to the right margin position, and inputted data is stored in an input buffer, and the data of the input buffer are printed respectively in the entirety at a predetermined print position in response to a print start command signal from a return key or the like.
Also, when the CTR mode is set, the carriage is moved to the center of the print line, and inputted data is stored in the input buffer, and the data of the input buffer are printed respectively in the entirety at a predetermined print position in response to the print start command signal from the return key or the like.
Furthermore, another configuration is also proposed to provide a measure of character input in a manner that when the RMF mode or the CTR mode is set, the carriage is moved to a predetermined position, thereafter a character is inputted, and then the carriage is moved by one character at a time in the counter printing direction (backspacing direction) from the right margin position every time a character is inputted in the RMF mode, and the carriage is moved by a half of character at a time in the counter printing direction every time a character is inputted in the CTR mode.
For example, in a word processor adapted for filling in blanks on preprinted forms which is disclosed in the U.S. Pat. No. 4,403,301, upon actuation of a character key, the carriage is moved relative to the record carrier without printing out the character in a special mode, and the character data fed-in are stored in a memory, and then the characters stored in the memory are printed out only upon receipt of a separate instruction signal which may be, for example, a special printout function signal, a carriage tabulation jump signal or a line shift signal.
However, in moving the carriage to provide this measure of character input, a positional deviation is produced at the first print position due to the backlash between gears and the elongation of a wire or belt in the driving mechanism driving the carriage. To eliminate this positional deviation, configuration is devised in a manner that the carriage is moved by a predetermined extra distance every time of movement in the counter printing direction, and thereafter the carriage is moved by a predetermined distance in the printing direction (spacing direction), and thereby the backlash of the carriage is corrected.
In the above-mentioned electronic typewriters, to eliminate the positional deviation every time of character input in the RMF mode or the CTR mode, configuration is made so as to compensate (correct) the backlash of the carriage. However, despite that printing is not executed, every time data is inputted before a print start command, unnecessary control of backlash compensation is performed, and therefore there exists a problem that extra vibration and noise attending on the backlash compensation are generated.